One increasingly popular computer network-based activity is referred to as “instant messaging” or IM communications, which is a form of RTC. An instant message is a form of electronic communication between users of a computer network in which a window pops-up on the recipient's computer screen “instantly” and without the recipient having to access an e-mail program or otherwise check for messages. An exchange of instant messages between two or more users may be referred to as an IM session. An instant message appears essentially as soon as the message sender clicks the send button subject to any time or propagation delays the message may have encountered on the network. In comparison to most e-mail applications, instant messaging permits users to communicate with each other in a more dynamic, urgent, and interactive manner.
Existing IM applications require a user, who wishes to engage in real time communications with others, to install a version of an instant messaging client on both sender's and recipient's computers. Other IM applications may require that the user is a subscriber, e.g., a user of a relevant on-line service bought from a service provider, in order to “chat” (exchange text-based messages) with other users. These requirements may present inconvenience to users who do not wish to become subscribers or install any additional software on their system, as well as to users who are subscribers but who are unable to “chat” (exchange text-based chat communications) with people who are not subscribers.